1. Field of the Invention
The present invention relates to armatures used in rotating electric machines, linear motors, and the like.
In response to developments of new technologies for various kinds of products using motors, there have been growing demands for space saving and high performance in rotating electric machines for driving, linear motors, and the like. In general, when a current flowing through a coil needs to be increased, the diameter of a wire for the coil is presumably increased; however, this increases rigidity of the coil, causing difficulty in winding the wire around its core. Therefore, often adopted is a method of making a coil wound around a core in a manner in which a wire having a smaller diameter is used so that the number of wire turns is increased. In a rotating electric machine including an armature provided with armature elements each having two coils, wires are wound in such a way that, in a region where the two coils abut each other, each upper winding is positioned on the trough created between lower adjacent windings, thereby aiming at reducing the dead spaces so as to realize a high density coil assembly (for example, Japanese Patent Laid-Open No. 2008-92654 (page 5-7, FIG. 2)).
2. Description of the Related Art
Rotating electric machines conventionally includes an armature provided with a plurality of armature elements composed of a plurality of pole teeth projecting radially inwardly from a ring-shaped yoke and coils wound around the pole teeth. In order to wind wires around such pole teeth, an automatic winding machine is used. To wind a wire around each of the pole teeth, the automatic winding machine moves a nozzle a coil-wire feeder to a position between the pole teeth; then, the automatic winding machine moves, feeding the wire from the tip of the nozzle, the nozzle in the yoke's central axis directions and in the yoke's radial directions while pivoting the yoke around the yoke's central axis. When accurately positioning, as described above, each upper winding layer on the trough created between lower adjacent windings, it is necessary to precisely control the position of the nozzle tip; however, the movement speed of the nozzle head is required to be increased for raising productivity, inevitably leading to an insufficient accuracy in positioning the nozzle tip.
A boundary plane between the two coils is determined by the outermost developed face of wire stack of the initially wound first coil, and respective positions of the windings in a conventional armature element depend only the location of the nozzle tip; then, the insufficient accuracy in positioning the nozzle tip due to the reasons mentioned above sometimes causes insufficient accuracy in positioning the windings, resulting in inaccurately determining the boundary plane and failing to form a neatly aligned winding in accordance with design drawings; this has led a problem in that it is difficult to practically produce high density windings.
The present invention is made to cope with the problems described above, and aims for an armature including a plurality of armature elements in each of which a boundary plane between two coil windings can be determined by their adjacent region and high density windings are realized by accurately winding wires in a neatly aligned manner.